I really like the syntax of the "magic methods" or whatever they are called in Python, like
class foo:
def __add__(self,other): #It can be called like c = a + b
pass
The call
c = a + b
is then translated to
a.__add__(b)
Is it possible to mimic such behaviour for "non-magic" functions? In numerical computations I need the Kronecker product, and am eager to have "kron" function such that
kron(a,b)
is in fact
a.kron(b)?
The use case is: I have two similar classes, say, matrix and vector, both having Kronecker product. I would like to call them
a = matrix()
b = matrix()
c = kron(a,b)
a = vector()
b = vector()
c = kron(a,b)
matrix and vector classes are defined in one .py file, thus share the common namespace. So, what is the best (Pythonic?) way to implement functions like above? Possible solutions:
1) Have one kron() functions and do type check
2) Have different namespaces
3) ?
The python default operator methods (__add__
and such) are hard-wired; python will look for them because the operator implementations look for them.
However, there is nothing stopping you from defining a kron
function that does the same thing; look for __kron__
or __rkron__
on the objects passed to it:
def kron(a, b):
if hasattr(a, '__kron__'):
return a.__kron__(b)
if hasattr(b, '__rkron__'):
return b.__rkron__(a)
# Default kron implementation here
return complex_operation_on_a_and_b(a, b)